In many cases, where the colon, the ileum or the urethra has been exposed surgically and the patient is left with an abdominal stoma, the effluents or waste products of the body, which are conveyed through these organs and discharged through the artificial orifice or opening and collected in a collection bag, the collection bag is usually adhered to the skin by means of an adhesive wafer or plate having an inlet opening for accommodating the stoma. Also, in connection with a fistula, the patient will also have to rely on an appliance to collect the bodily material emerging from such opening.
Often, an adhesive paste is used for filling the area between the stoma or fistula and a mounting gasket, ostomy washer and/or skin barrier or to build up an area on the abdomen around the stoma so as to provide a relatively flat and smooth surface onto which an appliance or skin barrier can be securely attached.
When used for adhering devices to the skin, the mouldability of the adhesive paste is very important in order to seal and fill in any irregularities and folds in the skin. On the other hand, a mouldable adhesive paste will, due to its higher degree of plasticity compared to elasticity or cohesiveness, have a tendency to flow away and leave openings between the device and the skin. Also, if a layer of adhesive paste with a backing layer is folded due to folds in the skin or otherwise, the adhesive paste may be pressed away from the backing, leaving parts of the backing with no adhesive, and thereby create leaks between the backing layer and the skin.
It has been found that by using a layered adhesive construction with a mouldable adhesive skin contact surface and a second layer of adhesive, which has a lower tendency to flow than the mouldable adhesive, between the backing layer and the mouldable adhesive, provides a construction with the advantages of a skin contact surface which is mouldable and a second layer providing a security against leakage.
It has also been found that the second adhesive layer may provide a certain rigidity to the layered construction which is an advantage with respect to preventing leakage and with respect to the tendency of leaving residues on the skin upon removal of the device.
Adhesive constructions comprising layers of hydrocolloid adhesives are well known in the art:
EP 1 527 789 A1 describes a construction comprising a film layer and at least two layers of hydrocolloid adhesives with different composition.
The prime object of the adhesive construction described therein is to provide a multi-layered adhesive medical appliance that has the attributes of a skin friendly wet tack pressure sensitive adhesive for use adjacent the skin, and a flexible, comfortable, moisture tolerant adhesive that resists degradation after sterilization, and is capable of creating a seal around the stoma in a controlled fashion, for use away from the skin.
It is described that a disadvantage of the known skin-friendly adhesives used adjacent to the skin is that they tend to be somewhat rigid when they become too thick. Thus according to this application, it is preferred that the adhesive layer adjacent to the skin is thinner than the more flexible, comfortable, moisture tolerant adhesive, which is use away from the skin.
EP 1 527 789 A1 also describes that one of the adhesive layers may be of a moldable hydrocolloid adhesive, but it is also apparent that the moldable adhesive layer in the construction is not the one of the two adhesive layers which is in contact with the skin, see paragraph 0033 of the reference.
EP 686 381 describes similar adhesive constructions with two layers of hydrocolloid adhesives with different composition. According to this patent application, the layer of adhesive securing the adhesive construction to the skin is composed of a skin friendly hydrocolloid containing adhesive that has a relatively low resistance to dissolution and/or disintegration when contacted by stomal fluids, whereas the other adhesive layer placed away from the skin is composed of a relatively soft, easy-deformable and extrudable adhesive sealant material that is more resistant to dissolution or disintegration by stomal fluids than the material of the skin contact adhesive. From the drawings it is clear that the adhesive layer adjacent to the skin is thinner than the adhesive layer placed away from the skin.
EP 413250 A1 describes an adhesive construction for use e.g. as part of an ostomy device, which comprises a backing layer and two layers of hydrocolloid adhesive. According to this document, both adhesive layers are in contact with the skin, the adhesive layer contacting the skin in the central part of the device being more than twice as thick as the adhesive layer contacting the skin in the peripheral portion of the construction.
U.S. Pat. No. 4,538,603 also describes and adhesive construction comprising two adhesive layers which may be of different composition, where the adhesive layer intended for skin contact is thicker than the adhesive layer placed away from the skin. The adhesive layer placed away from the skin is bonded to a foam layer carrying a film on the surface facing away from the adhesive layer. The adhesive construction described herein is useful for covering exudating wounds or ulcers. It is described that the relatively thick adhesive skin contact layer, is composed of ingredients permitting the adhesive construction to remain in place on the skin for several days. The water dispersible hydrocolloids, the water swellable cohesive strengthening agents and the hydratable polymers distributed throughout the adhesive layer gradually becomes hydrated over time. Eventually the adhesive layer becomes so hydrated that the construction can be removed without stripping or macerating the skin around the wound site. The relatively thick adhesive layer to be placed on the skin comprises thermoplastic elastomer, such as low molecular weight polyisobutylene, and hydrocolloids, water swellable cohesive strengthening agents and hydratable polymers, whereas the relatively thin adhesive layer placed away from the skin and bonded to the foam layer may also comprise plastizisers and tackifier.
WO 94/15562 describes adhesive constructions consisting of two adhesives, where one adhesive constitutes an island embedded in the other adhesive. It is described how the additional material unit which makes up the island may be of a less cohesive material and thereby more plastic, than the adhesive material making up the rest of the construct. The island may be a thicker or thinner layer than the other adhesive layer.
Layered adhesive constructions comprising a mouldable adhesive paste as the skin contact adhesive are described in GB 2290974, WO 98/17212 and WO98/53771. However, none of these constructions have a second adhesive layer between the layer of mouldable adhesive paste and the backing layer and in these constructions the paste is not used as the only adhesive means for attaching a medical device to the skin.